Characterization of the severe asthma phenotype by the National Heart, Lung, and Blood Institute's Severe Asthma Research Program

[Efficacy of biologics for severe asthma on allergic comorbidities]

Identification of therapeutic targets other than asthma can guide the choice of biologics in cases of severe asthma. Some of the allergic diseases (atopic dermatitis, food allergies, allergic rhinoconjunctivitis) that may be associated with asthma can be treated with biologics. In this review, we aim to assess the effectiveness of these biologic therapies on the allergic comorbidities of asthma. In the treatment of atopic dermatitis, only Dupilumab, an anti-IL4Rα, has proven its effectiveness and has received reimbursement authorization for this indication. In patients presenting with allergic rhinoconjunctivitis, Omalizumab has shown effectiveness, but has not been approved for this indication. Data from post-hoc analyses of studies on severe asthma likewise suggest the effectiveness of Dupilumab regarding allergic rhinitis. While these two biologic therapies have shown positive signals, inducing oral food tolerance, the relevant data are not robust. Biologic therapies targeting IL-5 or its receptor (Mepolizumab, Benralizumab) have seldom been evaluated in allergic comorbidities, excepting atopic dermatitis, for which their effectiveness has not been proven. Lastly, there are interesting data on the combination of biologic therapy and allergen immunotherapy in cases of allergic rhinitis and food allergies, but they need to be confirmed by randomized studies.

Multivariate Cluster Analyses to Characterize Asthma Heterogeneity and Benralizumab Responsiveness

BACKGROUND

An improved understanding of how severe asthma heterogeneity affects response could inform treatment decisions.

OBJECTIVES

Characterize heterogeneity and benralizumab responsiveness in patients grouped by predefined Severe Asthma Research Program clusters using a multivariate approach.

METHODS

In post-hoc analyses of the randomized, double-blind, placebo-controlled phase III SIROCCO (NCT01928771) and CALIMA (NCT01914757) studies, patients with severe asthma who received benralizumab or placebo were assigned to clusters using an established discriminant function to analyze 11 clinical characteristics simultaneously. The annualized asthma exacerbation rate, exacerbation incidence, and lung function were analyzed across clusters.

RESULTS

Patients (n = 2,281) met criteria for four of five clusters: cluster 2 (early-onset moderate asthma, n = 393), cluster 4 (early-onset severe asthma, n = 386), cluster 3 (late-onset severe asthma, n = 641), and cluster 5 (late-onset severe, obstructed asthma, n = 861); no patients met cluster 1 criteria. Exacerbation rate reductions were significant in late-onset severe asthma (-48% [95% CI, -61% to -31%]; P < .0001) and late-onset severe, obstructed asthma (-50% [95% CI, -59% to -38%]; P < .0001), with nonsignificant reductions in early-onset clusters. These differences could not be fully explained by blood eosinophil count differences. Values for improvements in FEV1 were significant in late-onset severe asthma (+133 mL [95% CI, 66-200]; P = .0001) and late-onset severe, obstructed asthma (+160 mL [95% CI, 85-235]; P < .0001) while maintaining acute bronchodilator responsiveness.

CONCLUSIONS

Benralizumab reduced exacerbations and improved lung function, primarily in late-onset asthma clusters. This multivariate approach to identify subphenotypes, potentially reflecting pathobiological mechanisms, can guide therapy beyond univariate approaches.

Baseline Characteristics and Maintenance Therapy Choice on Symptom Control, Reliever Use, Exacerbation Risk in Moderate-Severe Asthma: A Clinical Modelling and Simulation Study

INTRODUCTION

Although some factors associated with asthma symptom deterioration and risk of exacerbation have been identified, these are not yet fully characterised. We conducted a clinical modelling and simulation study to understand baseline factors affecting symptom control, reliever use and exacerbation risk in patients with moderate-severe asthma during follow-up on regularly dosed inhaled corticosteroid (ICS) monotherapy, or ICS/long-acting beta2-agonist (LABA) combination therapy.

METHODS

Individual patient data from randomised clinical trials (undertaken between 2001 and 2019) were used to model the time course of symptoms (n = 7593), patterns of reliever medication use (n = 3768) and time-to-first exacerbation (n = 6763), considering patient-specific and extrinsic factors, including treatment. Model validation used standard graphical and statistical criteria. Change in symptom control scores (Asthma Control Questionnaire 5 [ACQ-5]), reduction in reliever use and annualised exacerbation rate were then simulated in patient cohorts with different baseline characteristics and treatment settings.

RESULTS

Being a smoker, having higher baseline ACQ-5 and body mass index affected symptom control scores, reliever use and exacerbation risk (p < 0.01). In addition, low forced expiratory volume in 1 s percent predicted, female sex, season and previous exacerbations were found to contribute to a further increase in exacerbation risk (p < 0.01), whereas long asthma history was associated with more frequent reliever use (p < 0.01). These effects were independent from the underlying maintenance therapy. In different scenarios, fluticasone furoate (FF)/vilanterol was associated with greater reductions in reliever use and exacerbation rates compared with FF or fluticasone propionate (FP) alone or budesonide/formoterol, independently from other factors (p < 0.01).

CONCLUSIONS

This study provided further insight into the effects of individual baseline characteristics on treatment response and highlighted significant differences in the performance of ICS/LABA combination therapy on symptom control, reliever use and exacerbation risk. These factors should be incorporated into clinical practice as the basis for tailored management of patients with moderate-severe asthma.

Investigation of lactotransferrin messenger RNA expression levels as an anti-type 2 asthma biomarker

BACKGROUND

Lactotransferrin (LTF) has an immunomodulatory function, and its expression levels are associated with asthma susceptibility.

OBJECTIVES

We sought to investigate LTF messenger RNA (mRNA) expression levels in human bronchial epithelial cells (BECs) as an anti-type 2 (T2) asthma biomarker.

METHODS

Association analyses between LTF mRNA expression levels in BECs and asthma-related phenotypes were performed in the Severe Asthma Research Program (SARP) cross-sectional (n = 155) and longitudinal (n = 156) cohorts using a generalized linear model. Correlation analyses of mRNA expression levels between LTF and all other genes were performed by Spearman correlation.

RESULTS

Low LTF mRNA expression levels were associated with asthma susceptibility and severity (P < .025), retrospective and prospective asthma exacerbations, and low lung function (P < 8.3 × 10-3). Low LTF mRNA expression levels were associated with high airway T2 inflammation biomarkers (sputum eosinophils and fractional exhaled nitric oxide; P < 8.3 × 10-3) but were not associated with blood eosinophils or total serum IgE. LTF mRNA expression levels were negatively correlated with expression levels of TH2 or asthma-associated genes (POSTN, NOS2, and MUC5AC) and eosinophil-related genes (IL1RL1, CCL26, and IKZF2) and positively correlated with expression levels of TH1 and inflammation genes (IL12A, MUC5B, and CC16) and TH17-driven cytokines or chemokines for neutrophils (CXCL1, CXCL6, and CSF3) (P < 3.5 × 10-6).

CONCLUSIONS

Low LTF mRNA expression levels in BECs are associated with asthma susceptibility, severity, and exacerbations through upregulation of airway T2 inflammation. LTF is a potential anti-T2 biomarker, and its expression levels may help determine the balance of eosinophilic and neutrophilic asthma.

Molecular Pathways and Potential Therapeutic Targets of Refractory Asthma

Asthma is a chronic inflammatory lung disease. Refractory asthma poses a significant challenge in management due to its resistance to standard therapies. Key molecular pathways of refractory asthma include T2 inflammation mediated by Th2 and ILC2 cells, eosinophils, and cytokines including IL-4, IL-5, and IL-13. Additionally, non-T2 mechanisms involving neutrophils, macrophages, IL-1, IL-6, and IL-17 mediate a corticosteroid resistant phenotype. Mediators including alarmins (IL-25, IL-33, TSLP) and OX40L have overlap between T2 and non-T2 inflammation and may signify unique pathways of asthma inflammation. Therapies that target these pathways and mediators have proven to be effective in reducing exacerbations and improving lung function in subsets of severe asthma patients. However, there are patients with severe asthma who do not respond to approved therapies. Small molecule inhibitors, such as JAK-inhibitors, and monoclonal antibodies targeting mast cells, IL-1, IL-6, IL-33, TNFα, and OX40L are under investigation for their potential to modulate inflammation involved in refractory asthma. Understanding refractory asthma heterogeneity and identifying mediators involved are essential in developing therapeutic interventions for patients unresponsive to currently approved biologics. Further investigation is needed to develop personalized treatments based on these molecular insights to potentially offer more effective treatments for this complex disease.

The Glucocorticoid Receptor: Isoforms, Functions, and Contribution to Glucocorticoid Sensitivity

Glucocorticoids exert pleiotropic effects on all tissues to regulate cellular and metabolic homeostasis. Synthetic forms are used therapeutically in a wide range of conditions for their anti-inflammatory benefits, at the cost of dose and duration-dependent side effects. Significant variability occurs between tissues, disease states, and individuals with regard to both the beneficial and deleterious effects. The glucocorticoid receptor (GR) is the site of action for these hormones and a vast body of work has been conducted understanding its function. Traditionally, it was thought that the anti-inflammatory benefits of glucocorticoids were mediated by transrepression of pro-inflammatory transcription factors, while the adverse metabolic effects resulted from direct transactivation. This canonical understanding of the GR function has been brought into question over the past 2 decades with advances in the resolution of scientific techniques, and the discovery of multiple isoforms of the receptor present in most tissues. Here we review the structure and function of the GR, the nature of the receptor isoforms, and the contribution of the receptor to glucocorticoid sensitivity, or resistance in health and disease.

Methylprednisolone dosing for pediatric critical asthma: a single-center cohort study

OBJECTIVE

We aimed to characterize intravenous (IV) methylprednisolone (MP) dosing regimens and clinical outcomes for children hospitalized for critical asthma (CA).

METHODS

A single-center, retrospective review was performed of children admitted to the pediatric intensive care unit (PICU) for CA between September 2015 and October 2019. Patients 5-to 17-year-olds, initiated on continuous nebulized albuterol, and prescribed at least one dose of IV MP were included. The primary outcome was to characterize PICU MP dosing. Cohorts were then compared by MP dosing: conservative-dose methylprednisolone (CDMP, ≤ 0.5 mg/kg/dose every 6 h) and standard-dose methylprednisolone (SDMP, > 0.5 mg/kg/dose every 6 h). Clinical efficacy endpoints were the duration of continuous nebulized albuterol and PICU length of stay (LOS). Safety endpoints included corticosteroid-related adverse events.

RESULTS

Of 168 children studied, 50 (29.8%) were prescribed CDMP and 118 (70.2%) SDMP. The overall mean MP dose was 31.3 ± 19.6 mg (weight-adjusted: 0.77 ± 0.32 mg/kg/dose). Compared to those prescribed SDMP, those prescribed CDMP had a shorter median duration of continuous nebulized albuterol (12.8 [IQR: 10.5-20] versus 17.3 [IQR: 11.3-29.7] hours, p = 0.019) and median PICU LOS (0.9 [IQR: 0.7-1.4] versus 1.2 [IQR: 0.9-1.8] days, p = 0.012). No corticosteroid-related adverse events were observed. In adjusted models, weight-adjusted IV MP dose was not associated with PICU LOS or duration of continuous nebulized albuterol.

CONCLUSIONS

Intravenous MP dosing for pediatric CA varied widely in our study sample. Prospective, controlled trials are required to validate our observations including clinical efficacy and safety endpoints.

Activated non-neuronal cholinergic system correlates with non-type 2 inflammation and exacerbations in severe asthma

BACKGROUND

Non-neuronal cholinergic system (NNCS) contributes to various inflammatory airway diseases. However, the role of NNCS in severe asthma (SA) remains largely unexplored.

OBJECTIVE

To explore airway NNCS in SA.

METHODS

In this prospective cohort study based on the Australasian Severe Asthma Network in a real-world setting, patients with SA (n = 52) and non-SA (n = 104) underwent clinical assessment and sputum induction. The messenger RNA (mRNA) levels of NNCS components and proinflammatory cytokines in the sputum were detected using real-time quantitative polymerase chain reaction, and the concentrations of acetylcholine (Ach)-related metabolites were evaluated using liquid chromatography coupled with tandem mass spectrometry. Asthma exacerbations were prospectively investigated during the next 12 months. The association between NNCS and future asthma exacerbations was also analyzed.

RESULTS

Patients with SA were less controlled and had worse airway obstruction, a lower bronchodilator response, higher doses of inhaled corticosteroids, and more add-on treatments. The sputum mRNA levels of NNCS components, such as muscarinic receptors M1R-M5R, OCT3, VACHT, and ACHE; proinflammatory cytokines; and Ach concentration in the SA group were significantly higher than those in the non-SA group. Furthermore, most NNCS components positively correlated with non-type (T) 2 inflammatory profiles, such as sputum neutrophils, IL8, and IL1B. In addition, the mRNA levels of sputum M2R, M3R, M4R, M5R, and VACHT were independently associated with an increased risk of moderate-to-severe asthma exacerbations.

CONCLUSION

This study indicated that the NNCS was significantly activated in SA, leading to elevated Ach and was associated with clinical features, non-T2 inflammation, and future exacerbations of asthma, highlighting the potential role of the NNCS in the pathogenesis of SA.

CLINICAL TRIAL REGISTRATION

ChiCTR-OOC-16009529 (http://www.chictr.org.cn).

Eosinophil-mucus interplay in severe asthma: Implications for treatment with biologicals

Airway mucus is a hydrogel with unique biophysical properties due to its primary water composition and a small proportion of large anionic glycoproteins or mucins. The predominant mucins in human mucus, MUC5AC and MUC5B, are secreted by specialized cells within the airway epithelium both in normal conditions and in response to various stimuli. Their relative proportions are correlated with specific inflammatory responses and disease mechanisms. The dysregulation of mucin expression is implicated in numerous respiratory diseases, including asthma, COPD, and cystic fibrosis, where the pathogenic role of mucus has been extensively described yet often overlooked. In airway diseases, excessive mucus production or impaired mucus clearance leads to mucus plugging, with secondary airway occlusion that contribute to airflow obstruction, asthma severity and poor control. Eosinophils and Charcot Leyden crystals in sputum contribute to the mucus burden and tenacity. Mucin may also contribute to eosinophil survival. Other mechanisms, including eosinophil-independent IL-13 release, mast-cell activation and non-type-2 (T2) cytokines, are also likely to participate in mucus pathobiology. An accurate assessment of mucus and its clinical and functional consequences require a thorough approach that includes evaluation of cellular predominance in sputum, airway cytokines and other inflammatory markers, mucus characteristics and composition and structural and functional impact measured by advanced lung imaging. This review, illustrated with clinical scenarios, provides an overview of current methods to assess mucus and its relevance to the choice of biologics to treat patients with severe asthma.

Epidemiology of patients with severe asthma in Japan: a nationwide descriptive study

Background

The 2014 European Respiratory Society/American Thoracic Society guidelines defined severe asthma based on treatment intensity and estimated the proportion of severe asthma among all asthma cases to be 5-10%. However, data supporting the estimate and comprehensive and sequential data on asthma cases are scarce. We aimed to estimate the national prevalence and proportion of severe asthma during the last decade.

Methods

Using a Japanese national administrative database, which covers ≥99% of the population, we evaluated the prevalence and proportion of severe asthma in 2013, 2015, 2017 and 2019. Additionally, we elucidated the demographic characteristics, treatments and outcomes of patients with asthma.

Results

The national prevalence of mild-moderate and severe asthma in 2019 was 800 and 36 per 100 000 persons, respectively. While the prevalence of mild-moderate asthma remained almost constant in the study years, the prevalence of severe asthma decreased, resulting in a reduction in the proportion of severe asthma from 5.6% to 4.3%. Although treatment modalities have evolved, such as the increased use of combination inhalers and asthma biologics, approximately 15% of mild-moderate and 45% of severe asthma cases were still considered "uncontrolled". The number of deaths from asthma decreased in patients with both mild-moderate and severe asthma.

Conclusions

This study revealed that the prevalence of severe asthma in Japan decreased during the study period and fell below 5% in the most recent data. Despite treatment evolution, a substantial proportion of patients with both mild-moderate and severe asthma still have poor asthma control.

Characteristics of Severe Asthma in the Elderly: Observations From the Korean Severe Asthma Registry (KoSAR)

PURPOSE

Few studies have compared the clinical characteristics of severe asthma (SA) in elderly patients compared to that in nonelderly patients.

METHODS

We analyzed data from the Korean SA Registry, a nationwide, real-world observational study of SA in Korea. The baseline clinical characteristics, disease control status, and medication use of the patients were compared between elderly (≥ 65 years) and nonelderly groups.

RESULTS

Of the 864 patients with SA, 260 (30.1%) were in the elderly group. The elderly group had lower atopy rate, but had higher prevalence of chronic obstructive pulmonary disease (COPD), hypertension, and osteoporosis than did the nonelderly group. The elderly group had a lower rate of type 2 inflammation and lower levels of forced expiratory volume in 1 second (FEV1) (% predicted) and FEV1/forced vital capacity ratio than did the nonelderly group (P < 0.05 for all). However, asthma symptom scores and the frequency of asthma exacerbation were not significantly different between the 2 groups. Of controller medications, biologics were less frequently used in the elderly group (P < 0.05 for all).

CONCLUSIONS

SA in the elderly is characterized by lower lung function, less type 2-low airway inflammation, and comorbidity with COPD. These findings are being taken into consideration in the management of elderly patients with SA in real-world clinical practice.

The burden of severe asthma in sub-Saharan Africa: Findings from the African Severe Asthma Project

Background

Severe asthma is associated with high morbidity, mortality, and health care utilization, but its burden in Africa is unknown.

Objective

We sought to determine the burden (prevalence, mortality, and activity and work impairment) of severe asthma in 3 countries in East Africa: Uganda, Kenya, and Ethiopia.

Methods

Using the American Thoracic Society/European Respiratory Society case definition of severe asthma, we analyzed for the prevalence of severe asthma (requiring Global Initiative for Asthma [GINA] steps 4-5 asthma medications for the previous year to achieve control) and severe refractory asthma (remains uncontrolled despite treatment with GINA steps 4-5 asthma medications) in a cohort of 1086 asthma patients who had been in care for 12 months and had received all GINA-recommended medications. Asthma control was assessed by the asthma control questionnaire (ACQ).

Results

Overall, the prevalence of severe asthma and severe refractory asthma was 25.6% (95% confidence interval [CI], 23.1-28.3) and 4.6% (95% CI, 3.5-6.0), respectively. Patients with severe asthma were (nonsevere vs severe vs severe refractory) older (39, 42, 45 years, P = .011), had high skin prick test reactivity (67.1%, 76.0%, 76.0%, P = .004), had lower forced expiratory volume in 1 second percentage (81%, 61%, 55.5%, P < .001), had lower quality of life score (129, 127 vs 121, P < .001), and had higher activity impairment (10%, 30%, 50%, P < .001). Factors independently associated with severe asthma were hypertension comorbidity; adjusted odds ratio 2.21 (1.10-4.47), P = .027, high bronchial hyperresponsiveness questionnaire score; adjusted odds ratio 2.16 (1.01-4.61), P = .047 and higher ACQ score at baseline 2.80 (1.55-5.08), P = .001.

Conclusion

The prevalence of severe asthma in Africa is high and is associated with high morbidity and poor quality of life.

Identification of exhaled volatile organic compounds that characterize asthma phenotypes: A J-VOCSA study

BACKGROUND

Asthma is characterized by phenotypes of different clinical, demographic, and pathological characteristics. Identifying the profile of exhaled volatile organic compounds (VOCs) in asthma phenotypes may facilitate establishing biomarkers and understanding asthma background pathogenesis. This study aimed to identify exhaled VOCs that characterize severe asthma phenotypes among patients with asthma.

METHODS

This was a multicenter cross-sectional study of patients with severe asthma in Japan. Clinical data were obtained from medical records, and questionnaires were collected. Exhaled breath was sampled and subjected to thermal desorption gas chromatography-mass spectrometry (GC/MS).

RESULTS

Using the decision tree established in the previous nationwide asthma cohort study, 245 patients with asthma were divided into five phenotypes and subjected to exhaled VOC analysis with 50 healthy controls (HCs). GC/MS detected 243 VOCs in exhaled breath samples, and 142 frequently detected VOCs (50% of all samples) were used for statistical analyses. Cluster analysis assigning the groups with similar VOC profile patterns showed the highest similarities between phenotypes 3 and 4 (early-onset asthma phenotypes), followed by the similarities between phenotypes 1 and 2 (late-onset asthma phenotypes). Comparisons between phenotypes 1-5 and HC revealed 19 VOCs, in which only methanesulfonic anhydride showed p < 0.05 adjusted by false discovery rate (FDR). Comparison of these phenotypes yielded several VOCs showing different trends (p < 0.05); however, no VOCs showed p < 0.05 adjusted by FDR.

CONCLUSIONS

Exhaled VOC profiles may be useful for distinguishing asthma and asthma phenotypes; however, these findings need to be validated, and their pathological roles should be clarified.

Use of Quantitative CT Imaging to Identify Bronchial Thermoplasty Responders

BACKGROUND

Bronchial thermoplasty (BT) is a treatment for patients with poorly controlled, severe asthma. However, predictors of treatment response to BT are defined poorly.

RESEARCH QUESTION

Do baseline radiographic and clinical characteristics exist that predict response to BT?

STUDY DESIGN AND METHODS

We conducted a longitudinal prospective cohort study of participants with severe asthma receiving BT across eight academic medical centers. Participants received three separate BT treatments and were monitored at 3-month intervals for 1 year after BT. Similar to prior studies, a positive response to BT was defined as either improvement in Asthma Control Test results of ≥ 3 or Asthma Quality of Life Questionnaire of ≥ 0.5. Regression analyses were used to evaluate the association between pretreatment clinical and quantitative CT scan measures with subsequent BT response.

RESULTS

From 2006 through 2017, 88 participants received BT, with 70 participants (79.5%) identified as responders by Asthma Control Test or Asthma Quality of Life Questionnaire criteria. Responders were less likely to undergo an asthma-related ICU admission in the prior year (3% vs 25%; P = .01). On baseline quantitative CT imaging, BT responders showed less air trapping percentage (OR, 0.90; 95% CI, 0.82-0.99; P = .03), a greater Jacobian determinant (OR, 1.49; 95% CI, 1.05-2.11), greater SD of the Jacobian determinant (OR, 1.84; 95% CI, 1.04-3.26), and greater anisotropic deformation index (OR, 3.06; 95% CI, 1.06-8.86).

INTERPRETATION

To our knowledge, this is the largest study to evaluate baseline quantitative CT imaging and clinical characteristics associated with BT response. Our results show that preservation of normal lung expansion, indicated by less air trapping, a greater magnitude of isotropic expansion, and greater within-lung spatial variation on quantitative CT imaging, were predictors of future BT response.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01185275; URL: www.

CLINICALTRIALS

gov.

Tropical high altitude and severe asthma in adults: house dust mite sensitization and phenotypic distribution

BACKGROUND

There is a lack of information on house dust mite (HDM) sensitization and phenotype distribution in patients with severe asthma (SA) living permanently at high-altitude (HA) in tropical regions, which may be different.

OBJECTIVE

The aim of this study was to characterize adults with SA in a tropical high altitude city (2,640 m): Bogotá, Colombia.

MATERIAL AND METHODS

This observational cross-sectional study included severe asthmatic outpatients (n = 129) referred to the ASMAIRE program of the Fundación Neumológica Colombiana in Bogotá (2,640 m). Clinical history, spirometry, total IgE, blood eosinophils, and skin prick test (SPT), including HDM allergens, were performed. Phenotype definitions: Allergic/atopic (AA): IgE ≥100 IU/mL and/or at least one positive SPT; eosinophilic (EOS): blood eosinophils ≥300 cells/µL; type 2-high: AA and/or EOS phenotype; type 2-low: non-AA/non-EOS phenotype (IgE <100 IU/mL, negative SPT, and blood eosinophils <300 cells/µL).

RESULTS

A total of 129 adults with SA were included, 79.8% female. Phenotype distribution: AA: 61.2%; EOS: 37.2%; type 2-high: 72.1%; type 2-low: 27.9%. Among AA patients, HDM sensitization was present in 87% and 34.9% were non-eosinophilic. There was a significant overlap between the phenotypes.

CONCLUSIONS

In contrast to non-tropical high-altitude regions, we found a high frequency of HDM sensitization in patients with AA phenotype living in a tropical high-altitude city. We also found a discrete lower frequency of EOS phenotype with no other significant differences in the phenotypic distribution compared to that described at low altitudes. We propose that tropical location may modify the effect of high altitude on HDM concentrations and allergenicity.

Smoking, Urban Housing and Work-Aggravated Asthma are Associated with Asthma Severity in a Cross-Sectional Observational Study

Purpose

Severe asthma affects 5 to 10% of asthmatics and accounts for a large part of asthma-related morbidity and costs. The determinants of asthma severity are poorly understood. We tested the hypothesis that asthma severity was associated with 1) atopy and allergy and 2) markers associated with environmental exposure.

Patients and Methods

Data from the FASE-CPHG study, a cross-sectional, observational, multicenter investigation, were analyzed to identify markers associated with asthma severity. Asthma severity was gauged using the ASSESS score, encompassing symptom control, exacerbations, FEV1 and therapeutic load. Bivariate and multivariate analyses were used to identify patient characteristics associated with the ASSESS score.

Results

The analysis involved 948 patients, with 592 women, of which 447 patients (47%) had severe asthma. Among these, 491 patients (52%) had at least one positive aeroallergen skin prick test and 525 (55%) had at least one allergic disease among atopic dermatitis, chronic rhinitis and food allergy. The mean±SD ASSESS score was 11.2±3.4. Characteristics associated with a higher ASSESS score were female sex, secondary or lower education, unemployed occupational status, smoking, work-aggravated asthma and urban housing. There was no association between the ASSESS score and allergic diseases, aeroallergen-specific skin prick tests and IgEs, or blood eosinophil counts.

Conclusion

While atopy and allergy were frequent among asthmatics, neither was associated with asthma severity. Modifiable environmental factors such as smoking, urban housing and work-aggravated asthma were independently associated with asthma severity.

Moderate-High Blood Eosinophilia Is Associated with Increased Hospitalization and Other Asthma Comorbidities

(1) Background: Eosinophilia has traditionally been linked to eosinophilic asthma, for which it is the gold-standard prognostic biomarker. However, the association between eosinophilia and the presence of other diseases and comorbidities is yet unclear. (2) Methods: For this retrospective study, we reviewed the electronic medical records of 49,909 subjects with blood eosinophilia to gather data on the presence of asthma, COPD, sleep apnea, tuberculosis, dyslipidemia, hypertension, and other cardiovascular diseases and severe CRSwNP among these subjects. Demographic features including age, sex, and smoking habits were collected, as well as the number of hospitalizations and emergency department visits. T-tests, ANOVA, Fisher test, and logistic regression models were used. (3) Results: For all age groups studied, eosinophilia was significantly more prevalent among asthmatic subjects than nonasthmatics, especially in patients also presenting CRSwNP, hypertension, and dyslipidemia. The likelihood of developing asthma, COPD, and CRSwNP, and hospitalization, was increased when BEC was above 600 eosinophils/μL. The association between asthma, CRSwNP, and BEC was corroborated by multiple logistic regressions models. (4) Conclusions: We demonstrated the association of having over 600 blood eosinophils/μL with a higher number of hospitalizations and comorbidities (CRSwNP and COPD), which proves that BEC is a highly useful parameter to consider in subjects who present blood eosinophilia.

Effects of omalizumab on lung function in patients with moderate-to-severe allergic asthma: a systematic review and meta-analysis

BACKGROUND

With the rise of targeted treatments for asthma, treatment with omalizumab is a new option.

OBJECTIVES

To assess the improvement of pulmonary function with additional omalizumab treatment in patients (⩾6 years old) with moderate-to-severe allergic asthma.

DATA SOURCES AND METHODS

Observational studies of randomized controlled trials of add-on omalizumab for the treatment of patients with moderate-to-severe allergic asthma, published from the establishment till August 2022, were retrieved from WAN FANG DATA, PubMed, CNKI, Embase, Cochrane, and Web of Science databases. Data extraction and quality evaluation were performed on the literature that met the inclusion criteria, using RevMan 5.3 to analyze the data.

RESULTS

A total of 11 randomized controlled clinical trials were included, involving a total of 3578 patients with asthma, 1856 patients in the omalizumab group, and 1722 patients in the control group. The improvement in Forced expiratory volume in 1 s as a percentage of predicted normal and Forced expiratory volume in 1 s was more pronounced in the omalizumab-treated group [MD = 3.91, 95% confidence interval (CI): 1.89-5.94, p = 0.0002; MD = 0.09, 95% CI: 0.05-0.13, p < 0.0001], while the improvement in Morning Peak expiratory flow rate was not statistically different between the two groups (MD = 3.64, 95% CI: -22.17-29.45, p = 0.78).

CONCLUSION

Additional omalizumab treatment showed some improvement in lung function in patients with moderate-to-severe asthma.

TRIAL REGISTRATION

PROSPERO ID:CRD42022378498.

Glucocorticoids, their uses, sexual dimorphisms, and diseases: new concepts, mechanisms, and discoveries

The normal stress response in humans is governed by the hypothalamic-pituitary-adrenal (HPA) axis through heightened mechanisms during stress, raising blood levels of the glucocorticoid hormone cortisol. Glucocorticoids are quintessential compounds that balance the proper functioning of numerous systems in the mammalian body. They are also generated synthetically and are the preeminent therapy for inflammatory diseases. They act by binding to the nuclear receptor transcription factor glucocorticoid receptor (GR), which has two main isoforms (GRα and GRβ). Our classical understanding of glucocorticoid signaling is from the GRα isoform, which binds the hormone, whereas GRβ has no known ligands. With glucocorticoids being involved in many physiological and cellular processes, even small disruptions in their release via the HPA axis, or changes in GR isoform expression, can have dire ramifications on health. Long-term chronic glucocorticoid therapy can lead to a glucocorticoid-resistant state, and we deliberate how this impacts disease treatment. Chronic glucocorticoid treatment can lead to noticeable side effects such as weight gain, adiposity, diabetes, and others that we discuss in detail. There are sexually dimorphic responses to glucocorticoids, and women tend to have a more hyperresponsive HPA axis than men. This review summarizes our understanding of glucocorticoids and critically analyzes the GR isoforms and their beneficial and deleterious mechanisms and the sexual differences that cause a dichotomy in responses. We also discuss the future of glucocorticoid therapy and propose a new concept of dual GR isoform agonist and postulate why activating both isoforms may prevent glucocorticoid resistance.

Mitochondrial DNA Copy Number Variation in Asthma Risk, Severity, and Exacerbations

Rationale

Although airway oxidative stress and inflammation are central to asthma pathogenesis, there is limited knowledge of the relationship of asthma risk, severity, or exacerbations to mitochondrial dysfunction, which is pivotal to oxidant generation and inflammation.

Objectives

We investigated whether mitochondrial DNA copy number (mtDNA-CN) as a measure of mitochondrial function is associated with asthma diagnosis, severity, oxidative stress, and exacerbations.

Methods

We measured mtDNA-CN in blood in two cohorts. In the UK Biobank (UKB), we compared mtDNA-CN in mild and moderate-severe asthmatics to non-asthmatics. In the Severe Asthma Research Program (SARP), we evaluated mtDNA-CN in relation to asthma severity, biomarkers of oxidative stress and inflammation, and exacerbations.

Measures and Main Results

In UK Biobank, asthmatics (n = 29,768) have lower mtDNA-CN compared to non-asthmatics (n = 239,158) (beta, -0.026 [95% CI, -0.038 to -0.014], P = 2.46×10-5). While lower mtDNA-CN is associated with asthma, mtDNA-CN did not differ by asthma severity in either UKB or SARP. Biomarkers of inflammation show that asthmatics have higher white blood cells (WBC), neutrophils, eosinophils, fraction exhaled nitric oxide (FENO), and lower superoxide dismutase (SOD) than non-asthmatics, confirming greater oxidative stress in asthma. In one year follow-up in SARP, higher mtDNA-CN is associated with reduced risk of three or more exacerbations in the subsequent year (OR 0.352 [95% CI, 0.164 to 0.753], P = 0.007).

Conclusions

Asthma is characterized by mitochondrial dysfunction. Higher mtDNA-CN identifies an exacerbation-resistant asthma phenotype, suggesting mitochondrial function is important in exacerbation risk.

Living in environmental justice areas worsens asthma severity and control: Differential interactions with disease duration, age at onset, and pollution

BACKGROUND

Impoverished and historically marginalized communities often reside in areas with increased air pollution.

OBJECTIVE

We evaluated the association between environmental justice (EJ) track and asthma severity and control as modified by traffic-related air pollution (TRAP).

METHODS

We performed a retrospective study of 1526 adult asthma patients in Allegheny County, Pa, enrolled in an asthma registry during 2007-20. Asthma severity and control were determined using global guidelines. EJ tract designation was based on residency in census tracts with ≥30% non-White and/or ≥20% impoverished populations. TRAP exposures (NO2 and black carbon) for each census tract were normalized into pollution quartiles. Generalized linear model analyses determined the effect of EJ tract and TRAP on asthma.

RESULTS

TRAP exposure in the highest quartile range was more frequent among patients living in an EJ tract (66.4% vs 20.8%, P < .05). Living in an EJ tract increased the odds of severe asthma in later onset asthma. The odds of uncontrolled asthma increased with disease duration in all patients living in EJ tracts (P < .05). Living in the highest quartile of NO2 also increased the odds of uncontrolled asthma in patients with severe disease (P < .05), while there was no effect of TRAP on uncontrolled asthma in patients with less severe disease (P > .05).

CONCLUSIONS

Living in an EJ tract increased the odds of severe and uncontrolled asthma and was influenced by age at onset, disease duration, and potentially by TRAP exposure. This study underscores the need to better understand the complex environmental interactions that affect lung health in groups that have been economically and/or socially marginalized.

One-day systemic corticosteroid administration for asthma and future "short bursts" risk in real clinical practice

OBJECTIVE

Systemic corticosteroid administration, also called short bursts (SB), is harmful for patients with asthma; however, the actual burden of one-day SB remains unsolved. This study aimed to elucidate the characteristics of patients requiring one-day SB against asthma in clinical practice.

METHODS

Consecutive patients who regularly visited our hospital for asthma treatment between January 2019 and December 2020 were reviewed and followed for one year. SB was defined as ≥3 days of systemic corticosteroid treatment for an exacerbation. One-day SB was defined as one-day of systemic corticosteroid to treat an exacerbation. The one-day SB group included patients who received only one-day SB but no SB during the preceding year. Frequent SB was defined as that occurring ≥2 times/year.

RESULTS

Data on 229 patients were analyzed. Among them, 2.6% (95% confidence interval 1.2-5.6%) were in the one-day SB group. The one-day SB group was female-dominant, obese, non-eosinophilic, and non-atopic. The median one-day SB was 1.5 times/year and almost half of one-day SB were performed by patients themselves. Independent of the low pulmonary function, high blood eosinophil count, and inhaled corticosteroid dose, one-day SB was associated with future frequent SB (adjusted odds ratio = 18.2, 95% confidence interval 1.1-288, P = 0.040, compared to the no SB group).

CONCLUSIONS

Although one-day SB was not frequently experienced, even one-day SB without conventional SB was associated with future frequent SB. It is important to grasp the actual condition of one-day SB and to reinforce the treatment used.

Investigations of a combination of atopic status and age of asthma onset identify asthma subphenotypes

OBJECTIVE

Subphenotypes of asthma may be determined by age onset and atopic status. We sought to characterize early or late onset atopic asthma with fungal or non-fungal sensitization (AAFS or AANFS) and non-atopic asthma (NAA) in children and adults in the Severe Asthma Research Program (SARP). SARP is an ongoing project involving well-phenotyped patients with mild to severe asthma.

METHODS

Phenotypic comparisons were performed using Kruskal-Wallis or chi-square test. Genetic association analyses were performed using logistic or linear regression.

RESULTS

Airway hyper-responsiveness, total serum IgE levels, and T2 biomarkers showed an increasing trend from NAA to AANFS and then to AAFS. Children and adults with early onset asthma had greater % of AAFS than adults with late onset asthma (46% and 40% vs. 32%; P < 0.00001). In children, AAFS and AANFS had lower % predicted FEV1 (86% and 91% vs. 97%) and greater % of patients with severe asthma than NAA (61% and 59% vs. 43%). In adults with early or late onset asthma, NAA had greater % of patients with severe asthma than AANFS and AAFS (61% vs. 40% and 37% or 56% vs. 44% and 49%). The G allele of rs2872507 in GSDMB had higher frequency in AAFS than AANFS and NAA (0.63 vs. 0.55 and 0.55), and associated with earlier age onset and asthma severity.

CONCLUSIONS

Early or late onset AAFS, AANFS, and NAA have shared and distinct phenotypic characteristics in children and adults. AAFS is a complex disorder involving genetic susceptibility and environmental factors.

[Unmet Needs in Severe Allergic Asthma]

Severe asthma affects 3%-10% of the world's population, according to estimates by the Global Initiative for ASTHMA (GINA). Allergic asthma is one of the most common phenotypes of severe asthma and it is characterized by allergen-induced type 2 inflammation in which immunoglobulin E (IgE) is a key mediator, making it an important therapeutic target. The introduction of targeted biological therapies or treatments has entered the management for severe asthma in the era of precision medicine, and the goal of treatment is clinical remission of the disease. There is a significant percentage of patients with severe allergic asthma who do not respond to treatments and whose symptoms are not controlled. In this paper, a group of experts in the management of severe allergic asthma reviewed and evaluated the most relevant evidence regarding the pathophysiology and phenotypes of severe allergic asthma, the role of IgE in allergic inflammation, allergen identification, techniques, biomarkers and diagnostic challenges, available treatments and strategies for disease management, with a special focus on biological treatments. From this review, recommendations were developed and validated through a Delphi consensus process with the aim of offering improvements in the management of severe allergic asthma to the professionals involved and identifying the unmet needs in the management of this pathology.

The importance of specific IgE antibodies in the epidemiology of allergic rhinitis and asthma (ECAP survey): part four. The relationship between the concentration of specific IgE antibodies in serum and types of asthma

Introduction

Specific immunoglobulins E (sIgE) are important parameters for the estimation of severity of allergic diseases.

Aim

To determine the relationship between the concentration of specific IgE antibodies in serum and types of asthma.

Material and methods

The concentration of sIgE antibodies against allergens Dermatophagoides pteronyssinus, cat dander, timothy grass, and Alternaria alternata were determined in the serum of 4077 respondents randomly selected from 8 regions (ECAP study). The positive results of sIgE (≥ 0.35 IU/ml or ≥ 0.7 IU/ml) were correlated to clinical diagnosis (types of asthma, skin-prick tests).

Results

sIgE antibodies against any allergen were detected in 9.9% (classes 1-6)/7.6% (classes 2-6) of healthy respondents. Comparing sIgE antibodies of respondents with intermittent asthma to sIgE antibodies of respondents with persistent asthma, no statistically significant differences were identified. Relating to allergens of D. pteronyssinus, cat dander, and A. alternata, sIgE antibodies were more frequently detected in respondents with atopic asthma and a negative skin-prick test as compared to healthy respondents with a negative skin-prick test (p < 0.005 to p < 0.001). Relating to allergens of D. pteronyssinus, cat dander, and timothy grass, sIgE antibodies were more frequently detected in respondents with atopic asthma and a weakly positive skin-prick test as compared to healthy respondents with weakly positive skin-prick test (p < 0.05 to p < 0.001).

Conclusions

Regarding subjects with a negative or weakly positive skin test, when sIgE antibodies to the same allergen are detected, asthma is much more likely to occur.

Genetic analyses of chr11p15.5 region identify MUC5AC-MUC5B associated with asthma-related phenotypes

OBJECTIVE

Genome-wide association studies (GWASs) have identified single nucleotide polymorphisms (SNPs) in chr11p15.5 region associated with asthma and idiopathic interstitial pneumonias (IIPs). We sought to identify functional genes for asthma by combining SNPs and mRNA expression in bronchial epithelial cells (BEC) in the Severe Asthma Research Program (SARP).

METHODS

Correlation analyses of mRNA expression of six candidate genes (AP2A2, MUC6, MUC2, MUC5AC, MUC5B, and TOLLIP) and asthma phenotypes were performed in the longitudinal cohort (n = 156) with RNAseq in BEC, and replicated in the cross-sectional cohort (n = 155). eQTL (n = 114) and genetic association analysis of asthma severity (426 severe vs. 531 non-severe asthma) were performed, and compared with previously published GWASs of IIPs and asthma.

RESULTS

Higher expression of AP2A2 and MUC5AC and lower expression of MUC5B in BEC were correlated with asthma, asthma exacerbations, and T2 biomarkers (P < 0.01). SNPs associated with asthma and IIPs in previous GWASs were eQTL SNPs for MUC5AC, MUC5B, or TOLLIP, however, they were not in strong linkage disequilibrium. The risk alleles for asthma or protective alleles for IIPs were associated with higher expression of MUC5AC and lower expression of MUC5B. rs11603634, rs12788104, and rs28415845 associated with moderate-to-severe asthma or adult onset asthma in previous GWASs were not associated with asthma severity (P > 0.8).

CONCLUSIONS

SNPs associated with asthma in chr11p15.5 region are not associated with asthma severity neither with IIPs. Higher expression of MUC5AC and lower expression of MUC5B are risk for asthma but protective for IIPs.

Severe asthma trajectories in adults: findings from the NORDSTAR cohort

BACKGROUND

There is limited evidence on the pathways leading to severe asthma and we are presently unable to effectively predict the progression of the disease. We aimed to describe the longitudinal trajectories leading to severe asthma and to describe clinical events preceding disease progression in a nationwide population of patients with severe asthma.

METHODS

We conducted an observational study based on Swedish data from the NORdic Dataset for aSThmA Research (NORDSTAR) research collaboration platform. We identified adult patients with severe asthma in 2018 according to the European Respiratory Society/American Thoracic Society definition and used latent class analysis to identify trajectories of asthma severity over a 10-year retrospective period from 2018.

RESULTS

Among 169 128 asthma patients, we identified 4543 severe asthma patients. We identified four trajectories of severe asthma that were labelled as: trajectory 1 "consistently severe asthma" (n=389 (8.6%)), trajectory 2 "gradual onset severe asthma" (n=942 (20.7%)), trajectory 3 "intermittent severe asthma" (n=1685 (37.1%)) and trajectory 4 "sudden onset severe asthma" (n=1527 (33.6%)). "Consistently severe asthma" had a higher daily inhaled corticosteroid dose and more prevalent osteoporosis compared with the other trajectories. Patients with "gradual onset severe asthma" and "sudden onset severe asthma" developed type 2-related comorbidities concomitantly with development of severe asthma. In the latter group, this primarily occurred within 1-3 years preceding onset of severe asthma.

CONCLUSIONS

Four distinct trajectories of severe asthma were identified illustrating different patterns of progression of asthma severity. This may eventually enable the development of better preventive management strategies in severe asthma.

Airway epithelial development and function: A key player in asthma pathogenesis?

Though asthma is a common and relatively easy to diagnose disease, attempts at primary or secondary prevention, and cure, have been disappointing. The widespread use of inhaled steroids has dramatically improved asthma control but has offered nothing in terms of altering long-term outcomes or reversing airway remodeling and impairment in lung function. The inability to cure asthma is unsurprising given our limited understanding of the factors that contribute to disease initiation and persistence. New data have focused on the airway epithelium as a potentially key factor orchestrating the different stages of asthma. In this review we summarize for the clinician the current evidence on the central role of the airway epithelium in asthma pathogenesis and the factors that may alter epithelial integrity and functionality.

Histamine-releasing factor in severe asthma and rhinovirus-associated asthma exacerbation

BACKGROUND

Histamine-releasing factor (HRF) is implicated in allergic diseases. We previously showed its pathogenic role in murine models of asthma.

OBJECTIVE

We aim to present data analysis from 3 separate human samples (sera samples from asthmatic patients, nasal washings from rhinovirus [RV]-infected individuals, and sera samples from patients with RV-induced asthma exacerbation) and 1 mouse sample to investigate correlates of HRF function in asthma and virus-induced asthma exacerbations.

METHODS

Total IgE and HRF-reactive IgE/IgG as well as HRF in sera from patients with mild/moderate asthma or severe asthma (SA) and healthy controls (HCs) were quantified by ELISA. HRF secretion in culture media from RV-infected adenovirus-12 SV40 hybrid virus transformed human bronchial epithelial cells and in nasal washings from experimentally RV-infected subjects was analyzed by Western blotting. HRF-reactive IgE/IgG levels in longitudinal serum samples from patients with asthma exacerbations were also quantified.

RESULTS

HRF-reactive IgE and total IgE levels were higher in patients with SA than in HCs, whereas HRF-reactive IgG (and IgG1) level was lower in asthmatic patients versus HCs. In comparison with HRF-reactive IgElow asthmatic patients, HRF-reactive IgEhigh asthmatic patients had a tendency to release more tryptase and prostaglandin D2 on anti-IgE stimulation of bronchoalveolar lavage cells. RV infection induced HRF secretion from adenovirus-12 SV40 hybrid virus transformed bronchial epithelial cells, and intranasal RV infection of human subjects induced increased HRF secretion in nasal washes. Asthmatic patients had higher levels of HRF-reactive IgE at the time of asthma exacerbations associated with RV infection, compared with those after the resolution. This phenomenon was not seen in asthma exacerbations without viral infections.

CONCLUSIONS

HRF-reactive IgE is higher in patients with SA. RV infection induces HRF secretion from respiratory epithelial cells both in vitro and in vivo. These results suggest the role of HRF in asthma severity and RV-induced asthma exacerbation.

Management of comorbidities in difficult and severe asthma

Difficult-to-treat and severe asthma are challenging clinical entities. In the face of suboptimal asthma control, the temptation for clinicians is to reflexively escalate asthma-directed therapy, including increasing exposure to corticosteroids and commencement of costly but potent biologic therapies. However, asthma control is objectively and subjectively assessed based on measurable parameters (such as exacerbations or variability in pulmonary physiology), symptoms and patient histories. Crucially, these features can be confounded by common untreated comorbidities, affecting clinicians' assessment of asthma treatment efficacy.

Clinical Implications of Longitudinal Blood Eosinophil Counts in Patients With Severe Asthma

BACKGROUND

The stability and variability of blood eosinophil counts (BECs) to phenotype patients with severe asthma is not fully understood.

OBJECTIVE

This post hoc, longitudinal, pooled analysis of placebo-arm patients from 2 phase 3 studies evaluated the clinical implications of BEC stability and variability in moderate-to-severe asthma.

METHODS

This analysis included patients from SIROCCO and CALIMA who received maintenance medium- to high-dosage inhaled corticosteroids plus long-acting β2-agonists; 2:1 patients with BECs of 300 cells/μL or higher and less than 300 cells/μL were enrolled. The BECs were measured 6 times over 1 year in a centralized laboratory. Exacerbations, lung function, and Asthma Control Questionnaire 6 scores were documented across patients grouped by BEC (<300 cells/μL or ≥300 cells/μL) and variability (<80% or ≥80% BECs less than or greater than 300 cells/μL).

RESULTS

Among 718 patients, 42.2% (n = 303) had predominantly high, 30.9% (n = 222) had predominantly low, and 26.9% (n = 193) had variable BECs. Prospective exacerbation rates (mean ± SD) were significantly greater in patients with predominantly high (1.39 ± 2.20) and variable (1.41 ± 2.09) BECs versus predominantly low (1.05 ± 1.66) BECs. Similar results were observed for the number of exacerbations while on placebo.

CONCLUSIONS

Although patients with variable BECs had intermittently high and low BECs, they experienced similar exacerbation rates to the predominantly high group, which were greater than those in the predominantly low group. A high BEC supports an eosinophilic phenotype in clinical settings without additional measurements, whereas a low BEC requires repeated measurements because it could reflect intermittently high or predominantly low BECs.

Inadequate therapeutic responses to glucocorticoid treatment in bronchial asthma

Bronchial asthma (BA) is a heterogeneous disease. Some patients benefit greatly from glucocorticoid (GC) treatment, whereas others are non-responders. This could be attributable to differences in pathobiology. Thus, predicting the responses to GC treatment in patients with BA is necessary to increase the success rates of GC therapy and avoid adverse effects. The sustained inflammation in BA decreases glucocorticoid receptor (GR, NR3C1) function. Meanwhile, GRβ overexpression might contribute to GC resistance. Important factors in decreased GR function include p38 mitogen-activated protein kinase-dependent GR phosphorylated at Ser226, reduced expression of histone deacetylase 2 following activation of the phosphatidylinositol 3-kinase-δ signaling pathway, and increased nuclear factor-kappa B activity. MicroRNAs, which are involved in GC sensitivity, are considered biomarkers of the response to inhaled GCs. Some studies revealed that inflammatory phenotypes and disease-related modifiable factors, including infections, the airway microbiome, mental stress, smoking, and obesity, regulate individual sensitivity to GCs. Therefore, future investigations are warranted to improve treatment outcomes.

Pharmacogenetics of childhood uncontrolled asthma

INTRODUCTION

Asthma is a heterogeneous, multifactorial disease with multiple genetic and environmental risk factors playing a role in pathogenesis and therapeutic response. Understanding of pharmacogenetics can help with matching individualized treatments to specific genotypes of asthma to improve therapeutic outcomes especially in uncontrolled or severe asthma.

AREAS COVERED

In this review, we outline novel information about biology, pathways, and mechanisms related to interindividual variability in drug response (corticosteroids, bronchodilators, leukotriene modifiers, and biologics) for childhood asthma. We discuss candidate gene, genome-wide association studies and newer omics studies including epigenomics, transcriptomics, proteomics, and metabolomics as well as integrative genomics and systems biology methods related to childhood asthma. The articles were obtained after a series of searches, last updated November 2022, using database PubMed/CINAHL DB.

EXPERT OPINION

Implementation of pharmacogenetic algorithms can improve therapeutic targeting in children with asthma, particularly with severe or uncontrolled asthma who typically have challenges in clinical management and carry considerable financial burden. Future studies focusing on potential biomarkers both clinical and pharmacogenetic can help formulate a prognostic test for asthma treatment response that would represent true bench to bedside clinical implementation.

New insights into the pathophysiology and therapeutic targets of asthma and comorbid chronic rhinosinusitis with or without nasal polyposis

Asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) or without (CRSsNP) are chronic respiratory diseases. These two disorders often co-exist based on common anatomical, immunological, histopathological, and pathophysiological basis. Usually, asthma with comorbid CRSwNP is driven by type 2 (T2) inflammation which predisposes to more severe, often intractable, disease. In the past two decades, innovative technologies and detection techniques in combination with newly introduced targeted therapies helped shape our understanding of the immunological pathways underlying inflammatory airway diseases and to further identify several distinct clinical and inflammatory subsets to enhance the development of more effective personalized treatments. Presently, a number of targeted biologics has shown clinical efficacy in patients with refractory T2 airway inflammation, including anti-IgE (omalizumab), anti-IL-5 (mepolizumab, reslizumab)/anti-IL5R (benralizumab), anti-IL-4R-α (anti-IL-4/IL-13, dupilumab), and anti-TSLP (tezepelumab). In non-type-2 endotypes, no targeted biologics have consistently shown clinical efficacy so far. Presently, multiple therapeutical targets are being explored including cytokines, membrane molecules and intracellular signalling pathways to further expand current treatment options for severe asthma with and without comorbid CRSwNP. In this review, we discuss existing biologics, those under development and share some views on new horizons.

Relationship between aeroallergen sensitization pattern and clinical features in adult asthmatics

Background

Asthma can be classified into atopic and non-atopic phenotypes. However, limited data are available on the clinical implications of these two phenotypes in real life.

Objective

This study aimed to examine the clinical features as well as control level and disease severity of asthmatic patients with their aeroallergen sensitivity profiles.

Methods

Between 2013 and 2020, adult asthmatic patients who had been followed up regularly at our tertiary healthcare institution for at least one year were included in the study. We collected data retrospectively using manually filled patient files.

Results

The mean age of 382 asthmatic patients was 46.6 ± 30.0; 77.5% were women and 75.6% had at least one aeroallergen sensitivity. Polysensitized asthmatics had better asthma symptom control and milder asthma severity than monosensitized asthmatics. Asthma symptom control status was well controlled in 67.5% of the patients, and according to asthma severity, 51.3% of the patients were classified as having moderate asthma. There was a negative relation between age (OR:0.95, CI:0.92-0.98) and atopy presence. The presence of atopy was higher in moderate asthmatics than in mild asthmatics (OR:2.02, CI:1.01-4.09). Finally, there was a positive relationship between the percent predicted forced expiratory volume in first second (FEV₁%) (OR:1.02, CI:1.009-1.048) and the presence of atopy. The presence of rhinitis (OR:0.44, CI:0.22-0.88) and per 1 unit increase of Tiffeneau index (FEV₁/forced vital capacity) (OR:0.94, CI:0.90-0.99) had a negative association, whereas number of medication use for asthma symptoms (OR:1.68, CI:1.18-2.39) and presence of cardiovasculary disease (OR:2.64, CI:1.19-5.84) had a positive association with not well-controlled asthma symptom level.

Conclusion

Aeroallergen sensitivity was associated with asthma severity. However, this was not the case with asthma control levels in this adult asthma cohort. Among the atopic asthmatics polysensitized asthmatics had better asthma symptom control level and milder asthma severity level.

Safety, tolerability, and pharmacokinetics of a single ascending subcutaneous dose of GSK3772847 in healthy participants

The aim of this study was to evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of GSK3772847, compared with placebo administered subcutaneously (SC) in healthy participants, including cohorts of Japanese and Chinese participants. This was a single-center, randomized, placebo-controlled, double-blind, single ascending dose study. Following a screening period of up to 28 days, eligible participants were assigned to one of four cohorts receiving a single dose of GSK3772847 70 mg (cohort 1) or 140 mg (cohorts 2, 3, and 4) or placebo SC. In cohorts 1 and 2, participants were randomly assigned to one of three injection sites (upper arm, abdomen, or thigh), while cohorts 3 and 4 included Japanese and Chinese participants, respectively, assigned to receive GSK3772847 or placebo SC (upper arm). Participants attended follow-up visits on Days 9, 15, 29, 43, 57, 71, and 85 before final analysis. GSK3772847 was generally well tolerated. Most adverse events (AEs) were mild, resolved without treatment and were considered not related to study treatment by the investigator. There were no serious AEs or deaths during the study. The PK and PD were dose dependent, with negligible differences across injection sites or ethnicities. Target engagement was demonstrated by reduced free soluble interleukin 33 (sIL-33) concentrations and substantially increased total sIL-33 concentrations compared with baseline. Subcutaneously administered GSK3772847 was well tolerated in healthy participants, including cohorts of Japanese and Chinese participants, and shows consistent PK and PD across injection sites and ethnicities.

Dexamethasone versus methylprednisolone for critical asthma: A single center, open-label, parallel-group clinical trial

BACKGROUND

Evidence for the use of dexamethasone for pediatric critical asthma is limited. We sought to compare the clinical efficacy and safety of dexamethasone versus methylprednisolone among children hospitalized in the pediatric intensive care unit (PICU) for critical asthma.

METHODS

A prospective, single center, open-label, two-arm, parallel-group, nonrandomized trial among children ages 5-17 years hospitalized within the PICU from April 2019 to December 2021 for critical asthma consented to receive methylprednisolone (standard care) or dexamethasone (intervention) at a 2:1 allocation ratio, respectively. The intervention arm received intravenous dexamethasone 0.25 mg/kg/dose (max: 15 mg/dose) every 6 h for 48 h and the standard care arm intravenous methylprednisolone 1 mg/kg/dose every 6 h (max dose: 60 mg/dose) for 5 days. Study endpoints were clinical efficacy (i.e., length of stay [LOS], continuous albuterol duration, and a composite of adjunctive asthma interventions) and safety (i.e., corticosteroid-related adverse events).

RESULTS

Ninety-two participants were analyzed of whom 31 were allocated to the intervention arm and 61 the standard care arm. No differences in demographics, clinical characteristics, or acute/chronic asthma severity indices were observed. Regarding efficacy and safety endpoints, no differences in hospital LOS, continuous albuterol duration, adjunctive asthma intervention rates, or corticosteroid-related adverse events were noted. Compared to the intervention arm, participants in the standard care arm more frequently were prescribed corticosteroids at discharge (72% vs. 13%, p < 0.001).

CONCLUSIONS

Among children hospitalized for critical asthma, dexamethasone appears safe and warrants further investigation to fully assess clinical efficacy and potential advantages over commonly applied agents such as methylprednisolone.

Advances in respiratory physiology in mouse models of experimental asthma

Recent advances in mouse models of experimental asthma coupled with vast improvements in systems that assess respiratory physiology have considerably increased the accuracy and human relevance of the outputs from these studies. In fact, these models have become important pre-clinical testing platforms with proven value and their capacity to be rapidly adapted to interrogate emerging clinical concepts, including the recent discovery of different asthma phenotypes and endotypes, has accelerated the discovery of disease-causing mechanisms and increased our understanding of asthma pathogenesis and the associated effects on lung physiology. In this review, we discuss key distinctions in respiratory physiology between asthma and severe asthma, including the magnitude of airway hyperresponsiveness and recently discovered disease drivers that underpin this phenomenon such as structural changes, airway remodeling, airway smooth muscle hypertrophy, altered airway smooth muscle calcium signaling, and inflammation. We also explore state-of-the-art mouse lung function measurement techniques that accurately recapitulate the human scenario as well as recent advances in precision cut lung slices and cell culture systems. Furthermore, we consider how these techniques have been applied to recently developed mouse models of asthma, severe asthma, and asthma-chronic obstructive pulmonary disease overlap, to examine the effects of clinically relevant exposures (including ovalbumin, house dust mite antigen in the absence or presence of cigarette smoke, cockroach allergen, pollen, and respiratory microbes) and to increase our understanding of lung physiology in these diseases and identify new therapeutic targets. Lastly, we focus on recent studies that examine the effects of diet on asthma outcomes, including high fat diet and asthma, low iron diet during pregnancy and predisposition to asthma development in offspring, and environmental exposures on asthma outcomes. We conclude our review with a discussion of new clinical concepts in asthma and severe asthma that warrant investigation and how we could utilize mouse models and advanced lung physiology measurement systems to identify factors and mechanisms with potential for therapeutic targeting.

Efficacy of once-daily, single-inhaler, fixed-dose combination of mometasone/indacaterol/glycopyrronium in patients with asthma with or without persistent airflow limitation: Post hoc analysis from the IRIDIUM study

BACKGROUND

A novel, once-daily, fixed-dose combination of mometasone furoate/indacaterol acetate/glycopyrronium bromide (MF/IND/GLY) delivered via Breezhaler® is the first inhaled corticosteroid/long-acting ꞵ₂-agonist/long-acting muscarinic antagonist (ICS/LABA/LAMA) therapy approved for the maintenance treatment of asthma in adults inadequately controlled on ICS/LABA combination. In patients with asthma and persistent airflow limitation (PAL), maximal treatment, especially with combination is suggested. This post hoc analysis of data from the IRIDIUM study assessed the efficacy of MF/IND/GLY in asthma patients with and without PAL.

METHODS

Patients with post-bronchodilator FEV₁ ≤80% of predicted and FEV₁/FVC ratio of ≤0.7 were categorised as PAL subgroup and the remaining as the non-PAL subgroup. Lung function parameters (FEV₁, PEF, and FEF_25%-75%) and annualised asthma exacerbations rates were evaluated in both subgroups across the treatment arms: once-daily high-dose MF/IND/GLY (160/150/50 μg), high-dose MF/IND (320/150 μg) and twice-daily high-dose fluticasone/salmeterol (FLU/SAL; 500/50 μg).

RESULTS

Of the 3092 randomised patients, 64% (n = 1981) met the criteria for PAL. Overall, there was no evidence of treatment difference between PAL and non-PAL subgroups (interaction P-value for FEV₁, FEF_25%-75%, PEF, moderate or severe exacerbations, severe exacerbations and all exacerbations were 0.42, 0.08, 0.43 0.29, 0.35 and 0.12, respectively). In the PAL subgroup, high-dose MF/IND/GLY versus high-dose MF/IND and high-dose FLU/SAL improved trough FEV₁ (mean difference: 102 mL [P < 0.0001] and 137 mL [P < 0.0001]) and reduced moderate or severe (16% and 32%), severe (25% and 39%) and all exacerbations (19% and 38%), respectively.

CONCLUSIONS

Once-daily fixed-dose MF/IND/GLY was efficacious in asthma patients with and without persistent airflow limitation.

Distribution of type 2 biomarkers and association with severity, clinical characteristics and comorbidities in the BREATHE real-life asthma population

Background

Type 2 (T2) high asthma is recognised as a heterogenous entity consisting of several endotypes; however, the prevalence and distribution of the T2 biomarkers in the general asthma population, across asthma severity, and across compartments is largely unknown. The objective of the present study was to describe expression and overlaps of airway and systemic T2 biomarkers in a clinically representative asthma population.

Methods

Patients with asthma from the real-life BREATHE cohort referred to a specialist centre were included and grouped according to T2 biomarkers: blood and sputum eosinophilia (≥0.3×10⁹ cells·L^-1 and 3% respectively), total IgE (≥150 U·mL^-1), and fractional exhaled nitric oxide (≥25 ppb).

Results

Patients with mild-to-moderate asthma were younger (41 versus 49 years, p<0.001), had lower body mass index (25.9 versus 28.0 kg·m^-2, p=0.002) and less atopy (47% versus 58%, p=0.05), higher forced expiratory volume in 1 s (3.2 versus 2.8 L, p<0.001) and forced vital capacity (4.3 versus 3.9 L, p<0.001) compared with patients with severe asthma, who had higher blood (0.22×10⁹ versus 0.17×10⁹ cells·L^-1, p=0.01) and sputum (3.0% versus 1.5%, p=0.01) eosinophils. Co-expression of all T2 biomarkers was a particular characteristic of severe asthma (p<0.001). In patients with eosinophilia, sputum eosinophilia without blood eosinophilia was present in 45% of patients with mild-to-moderate asthma and 35% with severe asthma.

Conclusion

Severe asthma is more commonly associated with activation of several T2 pathways, indicating that treatments targeting severe asthma may need to act more broadly on T2 inflammatory pathways. Implementation of airway inflammometry in clinical care is of paramount importance, as the best treatable trait is otherwise is overlooked in a large proportion of patients irrespective of disease severity.

Low CC16 mRNA Expression Levels in Bronchial Epithelial Cells Are Associated with Asthma Severity

Rationale: CC16 is a protein mainly produced by nonciliated bronchial epithelial cells (BECs) that participates in host defense. Reduced CC16 protein concentrations in BAL and serum are associated with asthma susceptibility. Objectives: Few studies have investigated the relationship between CC16 and asthma progression, and none has focused on BECs. In this study, we sought to determine if CC16 mRNA expression levels in BECs are associated with asthma severity. Methods: Association analyses between CC16 mRNA expression levels in BECs (242 asthmatics and 69 control subjects) and asthma-related phenotypes in Severe Asthma Research Program were performed using a generalized linear model. Measurements and Main Results: Low CC16 mRNA expression levels in BECs were significantly associated with asthma susceptibility and asthma severity, high systemic corticosteroids use, high retrospective and prospective asthma exacerbations, and low pulmonary function. Low CC16 mRNA expression levels were significantly associated with high T2 inflammation biomarkers (fractional exhaled nitric oxide and sputum eosinophils). CC16 mRNA expression levels were negatively correlated with expression levels of Th2 genes (IL1RL1, POSTN, SERPINB2, CLCA1, NOS2, and MUC5AC) and positively correlated with expression levels of Th1 and inflammation genes (IL12A and MUC5B). A combination of two nontraditional T2 biomarkers (CC16 and IL-6) revealed four asthma endotypes with different characteristics of T2 inflammation, obesity, and asthma severity. Conclusions: Our findings indicate that low CC16 mRNA expression levels in BECs are associated with asthma susceptibility, severity, and exacerbations, partially through immunomodulation of T2 inflammation. CC16 is a potential nontraditional T2 biomarker for asthma development and progression.

Targeted GATA3 knockdown in activated T cells via pulmonary siRNA delivery as novel therapy for allergic asthma

GATA3 gene silencing in activated T cells displays a promising option to early-on undermine pathological pathways in the disease formation of allergic asthma. The central transcription factor of T helper 2 (Th2) cell cytokines IL-4, IL-5, and IL-13 plays a major role in immune and inflammatory cascades underlying asthmatic processes in the airways. Pulmonary delivery of small interfering RNAs (siRNA) to induce GATA3 knockdown within disease related T cells of asthmatic lungs via RNA interference (RNAi) presents an auspicious base to realize this strategy, however, still faces some major hurdles. Main obstacles for successful siRNA delivery in general comprise stability and targeting issues, while in addition the transfection of T cells presents a particularly challenging task itself. In previous studies, we have developed and advanced an eligible siRNA delivery system composed of polyethylenimine (PEI) as polycationic carrier, transferrin (Tf) as targeting ligand and melittin (Mel) as endosomolytic agent. Resulting Tf-Mel-PEI polyplexes exhibited ideal characteristics for targeted siRNA delivery to activated T cells and achieved efficient and sequence-specific gene knockdown in vitro. In this work, the therapeutic potential of this carrier system was evaluated in an optimized cellular model displaying the activated status of asthmatic T cells. Moreover, a suitable siRNA sequence combination was found for effective gene silencing of GATA3. To confirm the translatability of our findings, Tf-Mel-PEI polyplexes were additionally tested ex vivo in activated human precision-cut lung slices (PCLS). Here, the formulation showed a safe profile as well as successful delivery to the lung epithelium with 88% GATA3 silencing in lung explants. These findings support the feasibility of Tf-Mel-PEI as siRNA delivery system for targeted gene knockdown in activated T cells as a potential novel therapy for allergic asthma.

Clinical profiles of patients referred for biological therapy and major limitations in the qualification paths in a specialist asthma centre

Introduction

Despite the proven efficacy of biologics in the treatment of severe asthma, still a limited number of patients are included in the Polish therapeutic programme.

Aim

To identify major limitations in the qualification paths and predominant reasons leading to exclusion from available biologic treatments. The clinical profiles of patients referred for biologics were also examined.

Material and methods

Data on demographic characteristics, clinical profile, biomarkers, and medical history from one visit of patients that had been referred for qualification for biologics in 2018/2019 to the Barlicki Hospital (Poland) were collected. A comparison between eligible and ineligible patients was made.

Results

Within 2 years, only 116 patients had been referred to the biologic therapy of whom 93 (80%) had been suitable for the biologic programme. Criteria for the omalizumab programme included major limitations such as: frequent use of oral corticosteroids in the past, and serum total-IgE 30-1000 IU/ml, and for mepolizumab were blood eosinophil count (EOScount) > 350/μl and spirometric criterion. Ineligible patients had a significantly lower EOScount and better lung function than eligible individuals despite no significant differences in the number of exacerbations or quality of life between groups. A high percentage of ineligible patients had been referred to re-verify the diagnosis of severe asthma.

Conclusions

Potential limitations for biologic therapy include restrictive criteria limiting the group of patients to the most severe cases and referring patients with difficult-to-treat asthma without a differential diagnosis. Low awareness and knowledge among physicians who often are not familiar with qualification criteria require extensive education.

Impact of Anti-IL5 Therapies on Patients with Severe Uncontrolled Asthma and Possible Predictive Biomarkers of Response: A Real-Life Study

Severe Uncontrolled Asthma (SUA) counts for more than 25% of cases of severe asthma. The main factors that impair the quality of life of these patients are high doses of oral corticosteroids, the presence of exacerbations, and reduced lung function. The objective of this study was to evaluate, in real life, the clinical improvement of patients with SUA treated with anti-interleukin 5 (IL5) therapies: mepolizumab and benralizumab, together with the search for biomarkers associated with the response. We conducted a retrospective observational cohort study that included patients with severe uncontrolled eosinophilic asthma in a tertiary hospital receiving biological therapies. Three types of response were evaluated: improvement in lung function, reduction in exacerbations, and decrease in the use of oral corticosteroids. After 12 months of treatment, significant reductions were found in the number of exacerbations, the use of oral corticosteroids, and blood eosinophil levels for both biological therapies (p < 0.001). Lung function improved, achieving a significant improvement in %FEV1 (p < 0.001), as well as asthma control, with a significant increase in asthma control test (ACT) scores in both therapies. The markers associated with the corticosteroid-saving effect were the low doses of oral corticosteroids and absence of exacerbations for mepolizumab, and higher blood eosinophilia, absence of chronic obstructive pulmonary disease (COPD), and reduction in oral corticosteroid cycles for benralizumab. The greatest improvement in lung function in both therapies was linked to lower previous FEV1 levels and absence of other respiratory diseases. The reduction in exacerbations was associated with absence of exacerbations the previous year for mepolizumab and never smokers for benralizumab. The results of this real-life study confirm the clinical benefit obtained after the introduction of an anti-IL5 biological therapy and the possible predictive biomarkers of response to treatment.

Characterization and cluster analyses of elderly asthma in comparison with nonelderly patients with asthma in Japan

BACKGROUND

Asthma is a heterogeneous disease with multiple phenotypes that are useful in precision medicine. As the population ages, the elderly asthma (EA, aged ≥ 65 years) population is growing, and EA is now a major health problem worldwide.

OBJECTIVE

To characterize EA and identify its phenotypes.

METHODS

In adult patients with asthma (aged ≥ 18 years) who had been diagnosed with having asthma at least 1 year before study enrollment, 1925 were included in the NHOM-Asthma (registered in UMIN-CTR; UMIN000027776), and the data were used for this study, JFGE-Asthma (registered in UMIN-CTR; UMIN000036912). Data from EA and non-EA (NEA) groups were compared, and Ward's minimum-variance hierarchical clustering method and principal component analysis were performed.

RESULTS

EA was characterized by older asthma onset, longer asthma duration and smoking history, more comorbidities, lower pulmonary function, less atopic, lower adherence, and more hospital admissions because of asthma. In contrast, the number of eosinophils, total immunoglobulin E level, oral corticosteroid use, and asthma control questionnaire scores were equivalent between EA and NEA. There were 3 distinct phenotypes in EA, which are as follows: EA1: youngest, late onset, short duration, mild; EA2: early onset, long duration, atopic, low lung function, moderate; and EA3: oldest, eosinophilic, overweight, low lung function, most severe. The classification factors of the EA phenotypes included the age of onset and asthma control questionnaire-6. Similarities were observed between EA and NEA phenotypes after principal component analysis.

CONCLUSION

The EA in Japan may be unique because of the population's high longevity. Characterization of EA phenotypes from the present cohort indicated the need for distinct precision medicine for EA.

TRIAL REGISTRATION

JFGE-Asthma registered in UMIN-CTR (https://www.umin.ac.jp/ctr/); UMIN000036912.

Classifications of moderate to severe asthma phenotypes in Japan and analysis of serum biomarkers: A Nationwide Cohort Study in Japan (NHOM Asthma Study)

BACKGROUND

Asthma is a heterogeneous disease, and phenotyping can facilitate understanding of disease pathogenesis and direct appropriate asthma treatment. This nationwide cohort study aimed to phenotype asthma patients in Japan and identify potential biomarkers to classify the phenotypes.

METHODS

Adult asthma patients (n = 1925) from 27 national hospitals in Japan were enrolled and divided into Global Initiative for Asthma (GINA) steps 4 or 5 (GINA 4, 5) and GINA Steps 1, 2, or 3 (GINA 1-3) for therapy. Clinical data and questionnaires were collected. Biomarker levels among GINA 4, 5 patients were measured. Ward's minimum variance hierarchical clustering method and tree analysis were performed for phenotyping. Analysis of variance, the Kruskal-Wallis, and chi-square tests were used to compare cluster differences.

RESULTS

The following five clusters were identified: 1) late-onset, old, less-atopic; 2) late-onset, old, eosinophilic, low FEV₁; 3) early-onset, long-duration, atopic, poorly controlled; 4) early-onset, young, female-dominant, atopic; and 5) female-dominant, T1/T2-mixed, most severe. Age of onset, disease duration, blood eosinophils and neutrophils, asthma control questionnaire Sum 6, number of controllers, FEV₁, body mass index (BMI), and hypertension were the phenotype-classifying variables determined by tree analysis that assigned 79.5% to the appropriate cluster. Among the cytokines measured, IL-1RA, YKL40/CHI3L1, IP-10/CXCL10, RANTES/CCL5, and TIMP-1 were useful biomarkers for classifying GINA 4, 5 phenotypes.

CONCLUSIONS

Five distinct phenotypes were identified for moderate to severe asthma and may be classified using clinical and molecular variables (Registered in UMIN-CTR; UMIN000027776.).

Biomarkers in severe asthma: Identifying the treatable trait

Asthma is a chronic condition of bronchial hyper-reactivity associated with inflammation ranges from mild to severe form. It affects 1 - 18% of the population globally and it is estimated that > 300million people in the world have asthma. Of this 5 - 10% have severe asthma. while the proportion of patients suffering from severe are smaller, the morbidity and mortality are higher in this group. With the advances in our understanding of the pathophysiology of asthma there is a need to understand the role of various biomarkers. We live in an era of precision medicine and today there is a clear unmet need to understand targeted therapies. This review aims to raise awareness to the available biomarkers used in clinical practice in India and their role in predicting response to targeted therapies.

Remission outcomes in severe eosinophilic asthma with mepolizumab therapy: Analysis of the REDES study

Introduction

Clinical remission as a multicomponent treatment goal in severe asthma is being explored in clinical practice. This post hoc analysis used data from the REDES study to assess the proportion of patients with severe eosinophilic asthma achieving our multicomponent definitions of clinical remission after 1 year of mepolizumab treatment.

Methods

The real-world, retrospective observational REDES study enrolled patients with severe eosinophilic asthma who were newly prescribed mepolizumab and with ≥12 months of medical records pre-enrolment. Multicomponent clinical remission was defined as: oral corticosteroid (OCS)-free; exacerbation-free; asthma control test (ACT) score ≥20; and with or without post-bronchodilator forced expiratory volume in 1 second ≥80%. Baseline characteristics were also assessed in those who did/did not achieve clinical remission.

Results

37% and 30% of patients with severe eosinophilic asthma met our proposed three- and four-component on-treatment clinical remission definitions; an increase from 2% and 3% at baseline. Most frequently achieved individual components of clinical remission were: OCS-free; ACT score ≥20. For patients fulfilling the multicomponent clinical remission definitions, at baseline we observed higher blood eosinophil counts, better ACT scores and lung function, lower maintenance OCS use, and a slightly lower rate of prior exacerbations versus those who did not.

Discussion

Clinical remission is a realistic target in clinical practice for a subset of patients with severe eosinophilic asthma receiving mepolizumab. Further studies are required to elucidate whether features linked to the underlying endotype can help predict treatment outcomes, increase rates of clinical remission, and potentially modify disease progression.